I would like to connect two SPST SSRs A & B (125AC load, 3VDC input) to create a single SPDT SSR. One terminal on each SPST SSR will be connected together for the "common". The other terminal on SSR A will be connected to Line and the terminal on SSR B will be connected to Neutral. I will use two (2) GPIOs from my micro, making sure that both outputs are never high ('1').
(note: the "common" is connected to a motor coil. I would have a second SPDT arrangement on the other terminal of the coil. This will allow me to turn the motor CW or CCW. application: washing machine motor. a separate start coil (with a centrifugal switch) is used, which I am controlling via a single SPST.)
I also thought about using a single GPIO rather than two (for each SPDT). See attached picture - bottom. I am concerned about this approach since when the GPIO is switched, the SPSTs may momentarily be "on" at the same time, thus causing a short. Should I worry about this? (switching time is 1ms for the SSR's I'm using).
Any caveats or feedback on this approach? The only issue I see is if both GPIO's are high. This would cause a short between Line and Neutral, but through two SPSTs.
What would happen if this short were to occur?